The invention relates to a crimp connector for electrical contacting an electrical conductor embedded in an insulating layer. The invention further relates to a method for electrical contacting an electrical conductor embedded in an insulating layer by means of a crimp connector.
Crimp connectors are a fast, economical and reliable type of electrical connection for electrical conductors. Crimp connectors are preferably used in motor vehicle electronic devices where electrical connections are subjected to extremely rough environmental conditions and must have vibration stability, resistance to corrosion, temperature stability and current-carrying capacity.
The crimp connectors are commonly provided with corresponding piercing tines that are used as penetration connectors for contacting foil electrical conductors, such as flexible flat cables (FFC) or flexible printed circuit boards (FPC). An example of this type of crimp connector is shown in FIG. 16. The crimp connector of FIG. 16 has a base 108, which may be connected, for example, to a plug contact, and at least one piercing tine 104 that contacts an electrical conductor 122 of a flat conductor 124 by penetrating insulating material 120 provided thereon. The piercing tines 104 may be formed with a tapering, sharp-edge-type structure, so they cut into the electrical conductor 122 during assembly, as shown, for example, in U.S. Pat. No. 4,082,402 (Kincaid et al), U.S. Pat. No. 4,106,836 (Asick et al), U.S. Pat. No. 4,270,828 (Thurston) and U.S. Pat. No. 4,669,798 (Daum et al). During assembly, the piercing tines 104 are pressed downward with the aid of a suitable crimping tool in a direction of the electrical conductor 122 to penetrate the insulating material 120 and contact the electrical conductor 122.
U.S. Pat. No. 3,715,457 (Teagno et al) and U.S. Pat. No. 3,697,925 (Henschen) further teach the crimp connector with bent-up edges for providing strain relief in addition to the actual crimped contact. Additionally, U.S. Pat. No. 3,937,403 (Lawson) and U.S. Pat. No. 3,960,430 (Bunnell et al) teach contacting the electrical conductors embedded in the insulating material exclusively via contact projections formed on the base of the crimp connector. The piercing tines, thereby only mechanically fix the crimp connector to the flat conductor and do not penetrate the insulating material.
There is a problem, however, in that in the above-described crimp connectors, a layer of the insulating material remains between the base of the crimp connector and the electrical conductor to be contacted, whereby changes in shape, caused by, e.g., thermal changes in the insulating material, may have a negative effect on the quality of the electrical contact. For example, in the use of extruded flat conductors (exFLC) (which are increasingly employed in automobile construction, ship and aircraft cabling or industrial computers, because they are inexpensive and offer the advantage of more flexibility, space-saving and absolute water-tightness) where no prefabricated laminating foils have to be additionally bought and the plastics material sleeve is made directly from a granulate, the extruded foils may be subjected to high temperatures that cause the plastic materials of the insulating material to yield during thermal loading (U.S. Pat. No. 4,082,402 and U.S. Pat. No. 4,669,798).
A solution to this problem is accorded in U.S. Pat. No. 3,697,925 wherein the electrical conductor is stripped of the insulating material prior to attachment of the crimp connector. This solution, however, has the disadvantage in that defined removal of the insulating material is time-consuming and technically demanding. For example, this process requires the use of high-precision milling technology or expensive laser technology. Moreover, susceptibility to corrosion in the contact zone is increased, and mechanical stability is reduced.
An object of the invention therefore is to provide an improved crimp connector that can be assembled easily, inexpensively and efficiently while ensuring safe electrical contact even in cases where there are thermal changes in the properties of the insulating material.
This and other objects are achieved by a crimp connector having a crimping region including a base having at least one contact strip and at least one piercing tine. The at least one contact strip has a tapered tip and is arranged on the base such that the tapered tip penetrates an insulating material of a conductor from a lower surface to contact an electrical conductor therein when crimped. The at least one piercing tine has a tapered end region and is arranged on the base such that the tapered end region penetrates the insulating material of the conductor from an upper surface to contact the electrical conductor therein when crimped.
This and other objects are further achieved by a method for electrical contacting at least one electrical conductor embedded in an insulating material. A conductor is positioned adjacent to a contact strip arranged on base of a crimp connector. A piercing tine arranged on the base so that the crimp connector is deformed to at least partially encircle the conductor. An upper surface of the insulating material is penetrated with a tip of the piercing tine. A lower surface of the insulating material is penetrated with a tip of the contact strip. The respective tips of the piercing tine and the contact strip contact the electrical conductor.